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#+build darwin, netbsd, freebsd, openbsd
#+private
package mem_virtual
import "core:sys/posix"
_commit :: proc "contextless" (data: rawptr, size: uint) -> Allocator_Error {
if posix.mprotect(data, size, { .READ, .WRITE }) != .OK {
#partial switch posix.errno() {
case .EACCES, .EPERM: return .Invalid_Pointer
case .ENOTSUP, .EINVAL: return .Invalid_Argument
case: return .Out_Of_Memory
}
}
return nil
}
_release :: proc "contextless" (data: rawptr, size: uint) {
posix.munmap(data, size)
}
_protect :: proc "contextless" (data: rawptr, size: uint, flags: Protect_Flags) -> bool {
#assert(i32(posix.Prot_Flag_Bits.READ) == i32(Protect_Flag.Read))
#assert(i32(posix.Prot_Flag_Bits.WRITE) == i32(Protect_Flag.Write))
#assert(i32(posix.Prot_Flag_Bits.EXEC) == i32(Protect_Flag.Execute))
return posix.mprotect(data, size, transmute(posix.Prot_Flags)flags) == .OK
}
_platform_memory_init :: proc "contextless" () {
// NOTE: `posix.PAGESIZE` due to legacy reasons could be wrong so we use `sysconf`.
size := posix.sysconf(._PAGESIZE)
DEFAULT_PAGE_SIZE = uint(max(size, posix.PAGESIZE))
// is power of two
assert_contextless(DEFAULT_PAGE_SIZE != 0 && (DEFAULT_PAGE_SIZE & (DEFAULT_PAGE_SIZE-1)) == 0)
}
_map_file :: proc "contextless" (fd: uintptr, size: i64, flags: Map_File_Flags) -> (data: []byte, error: Map_File_Error) {
#assert(i32(posix.Prot_Flag_Bits.READ) == i32(Map_File_Flag.Read))
#assert(i32(posix.Prot_Flag_Bits.WRITE) == i32(Map_File_Flag.Write))
addr := posix.mmap(nil, uint(size), transmute(posix.Prot_Flags)flags, { .SHARED }, posix.FD(fd))
if addr == posix.MAP_FAILED || addr == nil {
return nil, .Map_Failure
}
return ([^]byte)(addr)[:size], nil
}
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